Discovering Inhibitors of Tyrosinase Enzyme from Zingiberaceae for Depigmentation Agents

摘要

Tyrosinase enzyme, which has two copper ions in its catalytic site, involved in skin pigmentation by catalyzing three oxidation reactions on melanogenesis, that are conversion of L-tirosine to L-DOPA, L-DOPA to dopaquinone, and 5,6-dihydroxyindole to 5, 6-indolequinone. An inhibition of melanogenesis was proven in vitro by bioactive compounds of Zingiberaceae plants, which are ethyl p-metoxycinnamate, galangin (IC_(50) 10μM), 6-gingerol (IC_(50) 25-100μM), 4-hydroxypanduratin-A (IC_(50) 23.2μM), isopanduratin-A (IC_(50) 10.6μM), kaempferol (IC_(50) 0.23μM), and kaempferida. In this paper we studied the interaction of these compounds with tyrosinase enzyme using AutoDock Vina. The interactions were then compared to arbutin (hydroquinone-β-D-glucoside), kojic acid, and hydroquinone, which have been well known as depigmentation agents in cosmetics. All bioactive compounds of Zingiberaceae plants were able to interact with tyrosinase. Compared to others, kaempferol showed the lowest inhibition constant value (Ki 2.7μM) and two metal interactions with both copper ions, Cu501 and Cu502, which means that this compound was predicted as the strongest inhibitor of tyrosinase enzyme. Kaempferol interacted with tyrosinase by blocking the entrance of the enzyme's catalytic site, therefore it will prevent the substrate to react with the enzyme. It can be concluded that bioactive compounds of Zingiberaceae can be developed as an inhibitors of tyrosinase.